day12- 练习（计算器的实现）

 public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("输入:");
        int x = scanner.nextInt();
        char a = scanner.next().charAt(0);
        int y = scanner.nextInt();
        switch (a){
            case '+':
                sum(x,y);
                break;
            case '-':
                sub(x,y);
                break;
            case '*':
                mul(x,y);
                break;
            case '/':
                div(x,y);
                break;
            default:
                System.out.println("输入错误");
        }
    }
    public static void sum(int a,int b){
        System.out.println(a+b);
    }
    public static void sub(int a,int b){
        System.out.println(a-b);
    }
    public static void mul(int a,int b){
        System.out.println(a*b);
    }
    public static void div(int a,int b){
        System.out.println(((double)a/b));
    }